The present invention is directed to an improved cylinder valve regulator for mounting on a high pressure gas cylinder for controlling the flow of gas from the cylinder. More particularly, the invention relates to an improved cylinder valve regulator which can significantly contribute to the safe handling of hazardous gases such as those used extensively in the semiconductor industry.
A known cylinder valve for controlling the flow of gas from a high pressure gas cylinder is a manually operated cylinder valve. When the high pressure gas cylinders contain hazardous gases such as those used in the semiconductor industry, the gas cylinders are placed in a gas cabinet which is ventilated for safety in the event of leaks. One problem associated with the use of the known manually operated cylinder valve in such an application is that it requires the operator to reach inside the gas cabinet to actuate the valves. The ingress and egress from the gas cabinet is time consuming and possibly dangerous to the operator in the event of gas leaks. One proposed solution to this problem involves the provision of a remotely controlled device within the gas cabinet to rotate the knob on the manually operated cylinder valves in the same manner as the operator would rotate the valves by hand. However, the provision of such an additional remote control device is problematical in that it requires additional space within the gas cabinet and represents an additional expense. Further, the remotely controlled devices are not fail safe since the manually operated valves may remain open in the event of loss of power to the remote control devices as, for example during a thunderstorm or earthquake.
Thus, an object of the present invention is to provide a cylinder valve regulator which avoids the aforementioned problems associated with the known manually operated cylinder valve. More specifically, an object of the invention is to provide a cylinder valve regulator which enables the operator to actuate the cylinder valve regulator from outside the gas cabinet, without having to reach inside the cabinet, which cylinder valve regulator safely closes itself upon failure of a valve control signal as in a power failure, for example.
A further object of the present invention is to provide a cylinder valve regulator for mounting on a high pressure gas cylinder for controlling the flow of gas from the cylinder which significantly contributes to the safety of handling of hazardous gases such as those used extensively in the semiconductor industry by permitting the remote control of the cylinder valve regulator to be subordinated to other parameters such as sensed earthquakes to effect an automatic closure of the cylinder valve to prevent gas leaks and possible injury.
An additional object of the present invention is to provide a cylinder valve regulator which can be mounted on a high pressure gas cylinder as a substitute for an existing hand operated valve, the cylinder valve regulator of the invention having a physical configuration to fit within the existing safety cap of the gas cylinder and incorporating a safety pressure device according to the Compressed Gas Association specification (CGAS 1.1) and which cylinder valve regulator has an outlet fitting meeting the configuration requirements of the CGA specifications.
These and other objects of the invention are attained by the cylinder valve regulator of the invention which is adapted to be mounted on a high pressure gas cylinder as a substitute for a hand operated valve for controlling the flow of gas from the cylinder. The cylinder valve regulator comprises means for mounting the cylinder valve regulator on the high pressure gas cylinder, fluid passage means for conveying gas through the cylinder valve regulator from an inlet for communicating with the high pressure gas cylinder to an outlet, first valve means for opening and closing the fluid passage means to control the flow of gas through the fluid passage means, and fluid pressure operated actuator means for operating the first valve means in response to the application of an external control pressure to the actuator means. The use of an external source of a control fluid pressure permits the remote control of the cylinder valve regulator so that the operator does not have to reach inside a gas cabinet to actuate the cylinder valve regulator. The safety of the operator is further enhanced by an additional feature of the invention wherein means are provided in the cylinder valve regulator for causing the first valve means to close the fluid passage means upon loss of the external control pressure to the actuator means. That is, in the event of a power failure during an earthquake or other catastrophe, the operator's safety is ensured to the extent possible by closure of the fluid passage means in the cylinder valve.
Safety in handling of hazardous gases is also further enhanced by an additional feature of the invention that the cylinder valve regulator is physically configured to fit within an existing safety cap for the high pressure gas cylinder on which the cylinder valve is mounted. Further, in the preferred form of the cylinder valve regulator a pressure safety device according to the CGA specification (CGA S1.1) is provided in the cylinder valve in fluid communication with the fluid passage means. The pressure safety device operates to release gas pressure in the valve above a safe operating temperature and/or pressure.
According to a disclosed, preferred embodiment of the invention the cylinder valve regulator further comprises second valve means located downstream of the first valve means in the vicinity of the outlet for opening and closing the fluid passage means to control the flow of gas through the fluid passage means. Means are provided for yieldably biasing the second valve means toward a position to close the fluid passage means. Further, means are provided for moving the second valve means to a position to open the fluid passage means in response to attachment of a connector to the outlet. Because of this a hazardous gas cannot be accidentally discharged from the cylinder valve regulator outlet when its accompanying gas conduit has not been attached to the outlet of the cylinder valve regulator.
In the disclosed embodiment the fluid pressure operated actuator means of the cylinder valve regulator is a pneumatically operated actuator for opening the first valve means in response to the application of an external control pressure to the actuator. The means for causing the first valve means to close the fluid passage means upon loss of external control pressure yieldably biases the first valve means toward a position to close the fluid passage means so that upon loss of the external control pressure to the actuator the first valve means closes the fluid passage means. The pneumatically operated actuator and the means for yieldably biasing the first valve means constitute or operate jointly as a pressure regulator means in the disclosed embodiment for operating the first valve means so as to regulate the gas pressure in the fluid passage means downstream of the first valve means in response to the application of the external control pressure to the actuator while effecting the fail safe mode, that is, closing the fluid passage means, upon loss of the external control pressure to the actuator.
More specifically, the pneumatically operated actuator comprises a piston-cylinder unit to which the external control fluid pressure is applied. Means are provided for transmitting movement of a piston of the piston-cylinder unit to the first valve means for opening the first valve means. The means for transmitting movement of the piston to the first valve means includes a movable diaphragm defining a portion of the fluid passage means downstream of the first valve means, means outside of the fluid passage means for transmitting the movement of the piston to the diaphragm, and means inside of the fluid passage means for transmitting movement of the diaphragm to the first valve means for opening the first valve means. With this arrangement the diaphragm moves so as to balance the opposing forces thereon from, on the one hand, the piston-cylinder unit as a result of the control pressure thereto, and, on the other hand, the gas pressure on the diaphragm downstream of the first valve means which corresponds to the outlet gas pressure. Thus, the valve opening at the first valve means is controlled to create downstream a pressure determined by the force applied by the actuator. Stated another way, the outlet pressure is related to the value of the control pressure to the actuator.
A one-way restrictor means is provided in the fluid passage means downstream of the first valve means, particularly between the second valve means and the outlet, for restricting the flow of gas flowing in the fluid passage means in the direction of the outlet. The restrictor means does not interfere with the reverse flow during the filling operation. To assist in the filling operation, an adapter can be applied to the pneumatic actuator to provide an override manual actuation as may be needed at the filling plant.
The materials of the cylinder valve regulator which contact the gas from the high pressure gas cylinder are resistant to hazardous gases including ammonia, silane, dichlorosilane, hydrogen chloride, arsine and phosphine and back-up seal means are provided in the cylinder valve regulator to protect against diaphragm failure.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, one embodiment in accordance with the present invention .